1. Field of the Invention
The present invention relates to an endoscope in which a bending portion is driven to be bent.
2. Description of the Related Art
In recent years, an endoscope has been widely used in a medical field and an industrial field. A bendable bending portion is provided on a distal end side of an insertion portion in the endoscope to make it easy to insert the endoscope into even a bent region.
The bending portion is coupled to an operation input portion for bending provided on a proximal end side of the insertion portion via a bending operation wire functioning as a traction member inserted through the insertion portion. An operator can tow the bending operation wire and bend the bending portion by pivoting a bending knob configuring the operation input portion.
When the bending portion is driven to be bent manually by the operator, a large operation force amount is necessary. Therefore, there is proposed an endoscope of an electric assist system in which a traction member is towed via electric driving means by tilting operation of a manipulator such as an operation lever or a joystick configuring an operation input portion.
For example, Japanese Patent Application Laid-Open Publication No. 2003-325437 discloses that a strained state of a bending operation wire corresponding to tilting operation fixed to a coupling member is changed by tilting a manipulator, whereby a C-ring member that is pivotably arranged on the outer side of a pulley rotated by a motor and around which the bending operation wire is wound is reduced in diameter, a friction force is generated between the C-ring member reduced in diameter and the pulley, the C-ring member is rotated together with the pulley, and the bending operation wire is moved in a direction of the rotation, whereby a bending portion is bent.
In this way, in the case of the endoscope of the electric assist system, compared with the manual bending of the bending portion, it is possible to bend the bending portion with a small operation force amount by the tilting operation of the manipulator.